Creating a Mixed-Initiative Grammar from Directed Dialog Grammars

ABSTRACT

A method of building a mixed-initiative grammar can include identifying a plurality of directed dialog grammars for inclusion in the mixed-initiative grammar and automatically generating the mixed-initiative grammar, in accordance with a selected grammar generation technique, such that the mixed-initiative grammar specifies the plurality of directed dialog grammars.

RESERVATION OF RIGHTS IN COPYRIGHTED MATERIAL

A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

FIELD OF THE INVENTION

The present invention relates to mixed-initiative speech-based systems and, more particularly, to creating grammars for use with such systems.

DESCRIPTION OF THE RELATED ART

Many robust voice applications utilize a form of human-computer interaction referred to as mixed-initiative interaction. Mixed-initiative interaction is a flexible interaction strategy between a user and a computer system in which each party can take a turn at any time to steer or alter the flow of interaction. Mixed-initiative systems provide a more natural, and generally preferred, manner for a user to interact with a computer system.

Within a mixed-initiative speech system, a user can provide different pieces of information in varying order without first being prompted for each individual item of information. The computer system can extract needed items of information from a user spoken utterance and use the items of information to fill in appropriate fields of an electronic form, for example. In illustration, a user can say, “I want to fly from Boston to New York, La Guardia on June 23^(rd)”. A mixed-initiative system can extract needed items of information such as the departure city, the arrival airport, and the date of the flight from that single spoken utterance. By comparison, a directed dialog system would prompt the user for each individual piece of information, one at a time, and perform the data collection in a particular order. In this manner, a directed dialog system effectively “directs” the flow of interaction or dialog without providing the user any opportunity to deviate from the specified flow.

One aspect of developing a mixed-initiative system is the development of a mixed-initiative grammar that will be used for processing user spoken utterances. While modern technologies such as Voice Extensible Markup Language (VoiceXML) support mixed-initiative dialogs, creating a mixed-initiative grammar within VoiceXML remains a complex undertaking. Typically, a mixed-initiative grammar is harder and more complex to develop and maintain than a directed dialog grammar. Such is the case as mixed-initiative grammars typically are built using directed dialog grammars as components. Further complicating mixed-initiative grammar development is the reality that these grammars are developed manually. As such, the creation of a mixed-initiative grammar can be a time consuming and error-prone process.

It would be beneficial to provide a more effective technique for creating mixed-initiative grammars which overcomes the deficiencies described above.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for constructing mixed-initiative grammars and further enables the reuse of directed dialog grammars. One embodiment of the present invention can include a method of building a mixed-initiative grammar. The method can include identifying a plurality of directed dialog grammars for inclusion in the mixed-initiative grammar and automatically generating the mixed-initiative grammar, in accordance with a selected grammar generation technique, such that the mixed-initiative grammar specifies the plurality of directed dialog grammars.

Another embodiment of the present invention can include a method of automatically constructing a mixed-initiative grammar from a plurality of directed dialog grammars. The method can include identifying a plurality of directed dialog grammars for inclusion in the mixed-initiative grammar and, responsive to a user prompt, receiving a user input specifying a selected grammar generation technique. The method further can include automatically generating the mixed-initiative grammar specifying the plurality of directed dialog grammars. The plurality of directed dialog grammars can have an ordered relationship relative to one another for processing a user spoken utterance that is determined, at least in part, according to the selected grammar generation technique.

Another embodiment of the present invention can include a machine readable storage, having stored thereon, a computer program having a plurality of code sections executable by a machine for causing the machine to perform the various steps and methods disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

There are shown in the drawings, embodiments which are presently preferred; it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown.

FIG. 1 is a pictorial view of a graphical user interface (GUI) for use in creating a mixed-initiative grammar in accordance with one embodiment of the present invention.

FIG. 2 is a pictorial view of a GUI for use in creating a mixed-initiative grammar in accordance with another embodiment of the present invention.

FIG. 3 depicts exemplary code illustrating one variety of mixed-initiative grammar that can be generated in accordance with the inventive arrangements disclosed herein.

FIG. 4 depicts exemplary code illustrating another variety of mixed-initiative grammar that can be generated in accordance with the inventive arrangements disclosed herein.

FIG. 5 depicts exemplary code illustrating yet another variety of mixed-initiative grammar that can be generated in accordance with the inventive arrangements disclosed herein.

FIG. 6 depicts exemplary code illustrating one manner in which a user can select and/or identify directed dialog grammars that are to be included within a mixed-initiative grammar.

FIG. 7 is a flow chart illustrating a method of creating a mixed-initiative grammar in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the description in conjunction with the drawings. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention.

The present invention provides a solution for developing a grammar for use by a mixed-initiative computing system. In accordance with the inventive arrangements disclosed herein, directed dialog grammars can be used, and/or reused, to create a mixed-initiative system. The present invention can elicit different items of information needed to create a mixed-initiative grammar from a user or software developer. In one embodiment, for example, one or more directed dialog grammars can be identified as well as various conjoin phrases. The conjoin phrases can be used to link selected ones of the directed dialog grammars. Using one of a plurality of different grammar generation techniques, a mixed-initiative grammar can be generated automatically from the user specified information, thereby reducing and/or eliminating many of the complexities typically associated with the manual creation of a mixed-initiative grammar.

In one embodiment, the inventive arrangements disclosed herein can be implemented within, or as part of, a software-based development system. For example, the various embodiments disclosed herein can be implemented as part of a software development system such as WebSphere® Voice Toolkit V6.0 (hereafter “Voice Toolkit”). Voice Toolkit is a software development platform that is available from International Business Machines Corporation of Armonk, N.Y. (IBM) which provides support for developing voice-enabled applications. Voice Toolkit provides a graphical grammar builder for visual composition of a grammar file for speech recognition, a communication flow builder that supports reusable dialog components, support for Voice Extensible Markup Language (VoiceXML), and/or other functions.

It should be appreciated that while the embodiments disclosed herein can be implemented as part of Voice Toolkit, such is but one embodiment. The present invention is not intended to be limited by the particular host application used as the embodiments disclosed herein can be provided as part of any suitable software-development system and/or environment. Moreover, it should be appreciated that the embodiments disclosed herein can be implemented as a standalone software development system or application.

FIG. 1 is a pictorial view of a graphical user interface (GUI) 100 for use in creating a mixed-initiative grammar in accordance with one embodiment of the present invention. GUI 100 can include a plurality of different field types 105, 110, and 115. Fields 105 and 115 can receive user inputs specifying various conjoin phrases. As shown, prefix type phrases can be received or specified in fields 105, while suffix type phrases can be specified in fields 115. Particular directed dialog grammars can be specified in fields 110. As used herein, a directed dialog grammar can specify one or more words or phrases that are allowable inputs for a particular field of an electronic form to be filled in based upon data extracted or recognized from one or more user spoken utterances.

FIG. 1 illustrates the case where a mixed-initiative grammar is being developed for a voice-enabled airline reservation system. It should be appreciated, however, that the inventive arrangements disclosed herein can be applied to any of a variety of different voice-enabled systems, and that the use of a particular industry in FIG. 1 was intended for purposes of illustration only. Accordingly, FIG. 1 is not intended to limit the present invention, but rather serve as a basis for explaining various aspects of the present invention.

In any case, referring again to fields 105 and 115, a conjoin phrase can serve as a queue indicating that a particular directed dialog grammar be used or, alternatively, to link two or more directed dialog grammars. A conjoin phrase can include one or more words, symbols, or textual elements as the case may be. Accordingly, when recognized within a user spoken utterance, a conjoin phrase indicates that a particular directed dialog grammar is to be used to process a given word or portion of the user spoken utterance. As noted, a conjoin phrase also can function to effectively link, or establish an association or relationship between, two or more directed dialog grammars. Accordingly, a conjoin phrase can establish an ordering between the directed dialog grammars that the conjoin phrase is used to link.

GUI 100 illustrates that the conjoin phrase “depart from”, where the word “depart” has been denoted as optional, has been associated with the directed dialog grammar named “departGrammar”. This grammar can specify a listing of departure cities. Similarly, the conjoin phrase “depart on”, where the word “depart” again is optional, has been associated with the directed dialog grammar named “departDate”. This grammar can specify a listing of dates. Thus, if a user says “depart from West Palm Beach on Wednesday”, for example, the conjoin phrase “depart from” indicates that the directed dialog grammar named “departGrammar” is to be used to recognized the next several word(s), i.e. “West Palm Beach” from the utterance. When the conjoin phrase “on” is recognized, the speech enabled system would determine that the “departDate” grammar is to be used to recognize the next several words, i.e. “Wednesday” from the utterance.

In this example, both conjoin phrases are classified as prefix phrases. Prefix conjoin phrases indicate that words following after the conjoin phrase within a user spoken utterance are to be processed using a particular directed dialog grammar. Accordingly, the word “Wednesday” is recognized using the “departGrammar”. A suffix conjoin phrase indicates that words preceding the conjoin phrase within a user spoken utterance are to be processed using a particular directed dialog grammar. As shown with GUI 100, directed dialog grammars can be associated with a prefix phrase, a suffix phrase, both a prefix and a suffix phrase, or neither type of conjoin phrase.

In one embodiment, directed dialog grammars can be specified by typing the names of the grammars into fields 110 of GUI 100. In another embodiment, drag and drop functionality can be used allowing a portion of code or a directed dialog grammar file to be selected and dropped over any one of fields 110. In yet another embodiment, a file selection navigation window can be opened to allow a user to select the directed dialog grammar(s). Such techniques also can be used to specify conjoin phrases.

FIG. 2 is a pictorial view of a GUI 200 for use in creating a mixed-initiative grammar in accordance with another embodiment of the present invention. GUI 200 allows a user to select any of a plurality of available grammar generation techniques to be used in creating the mixed-initiative grammar. In this case, there are three available grammar generation techniques shown in box 205. These techniques are fixed order, wide combination, and narrow combination.

GUI 200 further can include a field 220 which can receive a user provided input that specifies the initial prompt to be used to solicit information from an end user of the mixed-initiative system being developed. The initial prompt will be used to solicit the end user spoken utterance that will be processed using the mixed-initiative grammar being created. In an embodiment of the present invention using VoiceXML, for example, the prompt can be used with the “initial” tag. The “initial” tag is used within VoiceXML mixed-initiative dialogs to allow the user to fill in form-wide information. The “initial” tag permits the user to skip over a plurality of field prompts with one utterance. Usually, the first prompt in a mixed initiative dialog queries the user for all information. Typically, fields are executed only after it is determined that all field variables have not been filled. The “initial” element does not contain any grammars or filled events of its own; rather, it relies on the grammars and filled elements of each individual field.

The fixed order grammar generation technique is illustrated in view 210 of GUI 200. Using fixed order, a user can specify the particular order in which sets of a conjoin phrase and an associated directed dialog grammar, as specified or created in GUI 100, are ordered within the mixed-initiative grammar being generated. The user can select a particular conjoin phrase-directed dialog grammar set and move it up or down in the ordering using arrows 215. Using this technique, the mixed-initiative grammar will be created in a flat list of component directed dialog grammars.

FIG. 3 depicts exemplary code illustrating one variety of mixed-initiative grammar that can be generated in accordance with the inventive arrangements disclosed herein. More particularly, FIG. 3 illustrates the variety of mixed-initiative grammar that can be generated by the grammar generation tool based upon the options selected as shown with reference to FIG. 2.

FIG. 4 depicts exemplary code illustrating another variety of mixed-initiative grammar that can be generated in accordance with the inventive arrangements disclosed herein. More particularly, FIG. 4 depicts the variety of mixed-initiative grammar that can be generated by the grammar generation tool when the wide combination option is selected as the grammar generation technique. The wide combination grammar generation technique allows the user to say one or more or all of the directed dialog grammars in any ordering.

The wide combination grammar generation technique allows what can be referred to as “unintentional words” or “unintentional phrases” as the case may be. As can be seen in FIG. 4, an “*” syntax is used at the close of the mixed-initiative grammar. The “*” is a standard form of notation within various types of grammars such as Java Application Programming Interface Speech Grammar Format (OSGF), W3C Speech Recognition Grammar Specification (SRGS), Augmented Backus-Naur form (ABNF), or the like, which indicates that an expansion of the grammar can be spoken zero or more times. The term “phrase” as used herein can include one or more words, symbols, portions of text, or the like.

In illustration, the grammar illustrated in FIG. 4 would allow the user to speak the following phrases: “from Boston to Miami on May 1^(st)” and “on May 1^(st) to Miami from Boston”. The grammar also would allow the user to say the phrase “from Boston to Miami on May 1^(st) from Orlando”. This last user spoken utterance includes two instances of the departure city—“from Boston” and “from Orlando”. The grammar of FIG. 4 would permit such an utterance. The duplication of the departure city is referred to as an unintentional phrase and is permissible since the expansion of the grammar is allowed to be spoken zero or more times.

FIG. 5 depicts exemplary code illustrating yet another variety of mixed-initiative grammar that can be generated in accordance with the inventive arrangements disclosed herein. In particular, FIG. 5 depicts the variety of mixed-initiative grammar that can be generated by the grammar generation tool when the narrow combination option is selected as the grammar generation technique. The narrow combination option will generate a mixed-initiative grammar that will not only allow a user to say one or more or all of the dialog grammars in any order, but also will remove the list of unintentional phrases that are permissible when using the wide combination technique.

For example, assuming that a mixed-initiative grammar is to be made and that conjoin phrases and directed dialog grammars A, B, and C have been identified, the resulting mixed-initiative grammar would allow the following directed dialog orderings: A, B, C, AB, CA, BC, ABC, BAC, CAB, etc. Orderings such as AABC, AA, BCC, and the like would not, however, be acceptable. In this example, A represents the entire statement “([depart] from) <departGrammar>”, B represents the statement “(to | arrive at) <arrivalGrammar>”, and C represents ([depart] on) <departDate>”. Since unintentional phrases are not permissible, the entire utterance can be rejected if noncompliant or the unintentional phrase(s) can be ignored such that the remaining portion of the utterance can be processed. Notably, either the particular instance of any repeated phrase can be selected for processing based upon developer preference.

FIG. 6 depicts exemplary code illustrating one manner in which a user can select and/or identify those directed dialog grammars that are to be included within the mixed-initiative grammar being generated as well as the fields associated with each directed dialog grammar. Code such as that illustrated in FIG. 6 can be imported by the grammar generation tool, for example, through a file selection dialog or by dragging and dropping a text file including such code into a designated area of a GUI or onto an icon. In another embodiment, a user can drag and drop each individual directed dialog grammar to be included into the mixed-initiative grammar into the tool. In any case, the particular manner in which directed dialog grammars are specified or identified is not intended as a limitation of the present invention.

FIG. 7 is a flow chart illustrating a method 700 of creating a mixed-initiative grammar in accordance with yet another embodiment of the present invention. Method 700 can begin in step 705, where a user optionally can create one or more directed dialog grammars to be used in generating a mixed-initiative grammar for use with a mixed-initiative speech based system.

In step 710, the user can select one or more of the directed dialog grammars to be used in generating the mixed-initiative grammar. Since step 705 was optional in nature, the directed dialog grammars identified in step 710 need not have been created by the user, but may have been created by other developers. Accordingly, in step 710, the user can select one or more directed dialog grammars that are in existence, whether or not the user created the directed dialog grammars.

In step 715, the user can be prompted for one or more conjoin phrases. In step 720, a user input specifying one or more conjoin phrases can be received. It should be appreciated that the user input can be provided in such a way that not only are one or more conjoin phrases specified, but the conjoin phrases further can be associated with user specified directed dialog grammars, i.e. selected ones of those identified in step 710. In any case, steps 715 and 720 can be optional in nature as conjoin phrases may be excluded from a mixed-initiative grammar depending upon the particular grammar generation technique selected.

In step 725, the grammar generation tool can prompt the user for a specific grammar generation technique. In step 730, the user specified grammar generation technique can be received from the user as an input. In step 735, the grammar generation tool can prompt the user for an initial prompt to be used to solicit information from an end user. In step 740, the user specified initial prompt can be obtained or received from the user. In step 745, the grammar generation tool can generate the mixed-initiative grammar based upon the inputs and/or selections provided by the user. As noted, the order in which users are allowed to speak particular phrases, as dictated by the ordering of directed dialog grammars specified by the mixed-initiative grammar, can be dictated according to the grammar generation technique selected by the user.

It should be appreciated that the various GUI's, flow charts, and example portions of code disclosed herein have been provided for purposes of illustration only and, as such, are not intended to limit the scope of the present invention in any way. With respect to the GUI's, for example, different controls, visual indicators, and the like can be used in lieu of those shown and/or discussed. Similarly, with respect to the flow chart, various steps can be omitted or performed in a different order than described without departing from the spirit of the invention.

The present invention can be realized in hardware, software, or a combination of hardware and software. The present invention can be realized in a centralized fashion in one computer system or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware and software can be a general-purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein. The present invention also can be embedded in a computer program product, which comprises all the features enabling the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods.

The terms “computer program”, “software”, “application”, variants and/or combinations thereof, in the present context, mean any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form. For example, a computer program can include, but is not limited to, a subroutine, a function, a procedure, an object method, an object implementation, an executable application, an applet, a servlet, a source code, an object code, a shared library/dynamic load library and/or other sequence of instructions designed for execution on a computer system.

The terms “a” and “an”, as used herein, are defined as one or more than one. The term “plurality”, as used herein, is defined as two or more than two. The term “another”, as used herein, is defined as at least a second or more. The terms “including” and/or “having”, as used herein, are defined as comprising (i.e., open language). The term “coupled”, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically, i.e. communicatively linked through a communication channel or pathway.

This invention can be embodied in other forms without departing from the spirit or essential attributes thereof. Accordingly, reference should be made to the following claims, rather than to the foregoing specification, as indicating the scope of the invention. 

1. A method of building a mixed-initiative grammar comprising: identifying a plurality of directed dialog grammars for inclusion in the mixed-initiative grammar; and automatically generating the mixed-initiative grammar, in accordance with a selected grammar generation technique, such that the mixed-initiative grammar specifies the plurality of directed dialog grammars.
 2. The method of claim 1, further comprising receiving at least one conjoin phrase, wherein each conjoin phrase is associated with a selected one of the plurality of directed dialog grammars, wherein the conjoin phrase, when recognized within a user spoken utterance, indicates that the associated directed dialog grammar is to be used to process a specific portion of the user spoken utterance.
 3. The method of claim 2, said generating step further comprising including a plurality of sets within the mixed-initiative grammar, wherein each set specifies a conjoin phrase and an associated directed dialog grammar and the selected grammar generation technique specifies that the sets of the mixed-initiative grammar are to be used in a fixed order to interpret a user spoken utterance.
 4. The method of claim 2, said generating step further comprising including a plurality of sets within the mixed-initiative grammar, wherein each set specifies a conjoin phrase and an associated directed dialog grammar, wherein the selected grammar generation technique specifies that the sets of the mixed-initiative grammar are to be used in any order to interpret a user spoken utterance, wherein the selected grammar generation technique allows unintentional phrases.
 5. The method of claim 1, wherein the selected grammar generation technique dictates that the plurality of directed dialog grammars specified by the mixed-initiative grammar are usable in any order to interpret a user spoken utterance such that unintentional phrases are ignored.
 6. The method of claim 2, said receiving step further comprising first prompting a user by presenting a graphical user interface having an input area for receiving at least one user-specified conjoin phrase.
 7. The method of claim 6, wherein the graphical user interface comprises an input area for receiving at least one prefix conjoin phrase and an input area for receiving at least on suffix conjoin phrase.
 8. A method of automatically constructing a mixed-initiative grammar from a plurality of directed dialog grammars, said method comprising: identifying a plurality of directed dialog grammars for inclusion in the mixed-initiative grammar; responsive to a user prompt, receiving a user input specifying a selected grammar generation technique; and automatically generating the mixed-initiative grammar specifying the plurality of directed dialog grammars, wherein the plurality of directed dialog grammars have an ordered relationship relative to one another for processing a user spoken utterance that is determined, at least in part, according to the selected grammar generation technique.
 9. The method of claim 8, further comprising responsive to a user prompt, receiving a user input specifying at least one conjoin phrase which identifies at least one of the plurality of directed dialog grammars to be used in processing a selected portion of the user spoken utterance, wherein the at least one conjoin phrase is specified by the mixed-initiative grammar.
 10. The method of claim 9, wherein the mixed-initiative grammar is comprised of a plurality of sets, with each set specifying a conjoin phrase and an associated directed dialog grammar, wherein the selected grammar generation technique dictates that the sets are usable in a fixed order to interpret a user spoken utterance.
 11. The method of claim 9, wherein the mixed-initiative grammar is comprised of a plurality of sets, with each set specifying a conjoin phrase and an associated directed dialog grammar, wherein the selected grammar generation technique dictates that the sets are usable in any order to interpret a user spoken utterance, wherein the selected grammar generation technique allows unintentional phrases.
 12. The method of claim 8, wherein the mixed initiative grammar dictates that the directed dialog grammars used to generate the mixed-initiate grammar are usable in any order to interpret a user spoken utterance irrespective of unintentional phrases.
 13. The method of claim 8, further comprising, responsive to a prompt, receiving a user input specifying an initial prompt to be played by a mixed-initiative system, wherein the initial prompt is used to elicit a user spoken utterance that is to be processed using the mixed-initiative grammar created in said generating step.
 14. A machine readable storage, having stored thereon a computer program having a plurality of code sections comprising: code for identifying a plurality of directed dialog grammars for inclusion in the mixed-initiative grammar; and code for automatically generating the mixed-initiative grammar, in accordance with a selected grammar generation technique, such that the mixed-initiative grammar specifies the plurality of directed dialog grammars.
 15. The machine readable storage of claim 14, further comprising code for receiving at least one conjoin phrase, wherein each conjoin phrase is associated with a selected one of the plurality of directed dialog grammars, wherein the conjoin phrase, when recognized within a user spoken utterance, indicates that the associated directed dialog grammar is to be used to process a specific portion of the user spoken utterance.
 16. The machine readable storage of claim 15, said code for generating further comprising code for including a plurality of sets within the mixed-initiative grammar, wherein each set specifies a conjoin phrase and an associated directed dialog grammar and the selected grammar generation technique specifies that the sets of the mixed-initiative grammar are to be used in a fixed order to interpret a user spoken utterance.
 17. The machine readable storage of claim 15, said code for generating further comprising code for including a plurality of sets within the mixed-initiative grammar, wherein each set specifies a conjoin phrase and an associated directed dialog grammar, wherein the selected grammar generation technique specifies that the sets of the mixed-initiative grammar are to be used in any order to interpret a user spoken utterance, wherein the selected grammar generation technique allows unintentional phrases.
 18. The machine readable storage of claim 14, wherein the selected grammar generation technique dictates that the plurality of directed dialog grammars specified by the mixed-initiative grammar are usable in any order to interpret a user spoken utterance such that unintentional phrases are ignored.
 19. The machine readable storage of claim 15, said code for receiving further comprising code for first prompting a user by presenting a graphical user interface having an input area for receiving at least one user-specified conjoin phrase.
 20. The machine readable storage of claim 19, wherein the graphical user interface comprises an input area for receiving at least one prefix conjoin phrase and an input area for receiving at least on suffix conjoin phrase. 